Die casting machine



July 31, 1962 H. c. WERNECKE 3,045,622

DIE CASTING MACHINE Original Filed Jan. 2, 1958 2 Sheets-Sheet 1 MW/uuJuly 31, 1962 H. c. WERNECKE 3,046,622

DIE CASTING MACHINE Original Filed Jan. 2, 1958 2 Sheets-Sheet 2INVENTOR. 44w: MAW/V521? 3,046,622 Patented July 31, 1962 [l he purposeof removing finished work pieces and into which molten casting materialis injected under pressure. More particularly this invention relates tospecial mechanism for opening and closing the die halves and for lockingthe die halves in a closed position in such a secure manner as to resistthe opening forces exerted by the pressured injection of the moltencasting material.

Die casting machines generally employ two cooperating die halves, one ofwhich is fixed relative to the machine base and a second which ismovable with respect to the first so as to be disposable in a firstclosed position in which the casting operation is performed and a secondopen position in which the finished casting may be removed from betweenthe dies. When the dies are in a closed position molten casting materialis injected into the cavity between them under high pressure so as toinsure that the cavity becomes completely filled with the material. Thisinjection pressure acts to separate the die halves from one another. Ifany separating motion does occur during the injection the dimensions ofthe finished casting will be affected. Also, die separation duringinjection may allow the molten casting material to spray out of the diecavity along the parting line so as'to endanger the operation. For thesereasons it is essential. that the die halves be rigidly locked togetherduring the casting portion of the cycle.

Present casting machines generally utilize a single mechanism for movingthe die halves with respect to one another and for locking them in aclosed position. Commonly this mechanism includes a linkage which hasone end directly connected to the movable die half and the other endconnected to the fixed die half through the rods which also act asguides for the movable die half. These tie rods therefore extend fromthe fixed die half to the far end of the linkage. Because of the lengthof the connection thus formed between the fixed and the movable diehalves, temperature changes often affect the exact positioning of thedies with respect to one another. Additionally, the connections in thelinkage make it difficult to achieve exact positioning of the movabledie half.

The present invention contemplates a die closing and locking mechanismfor die casting machines in which the die moving and die locking actionsare accomplished by separate mechanisms so that it is possible to have ashort, direct, inflexible connection between the dies when they are in aclosed position.

In essence, the present invention provides a unique form of hydrauliccylinder and piston which performs the sole function of transferring themovable die half toward and away from the fixed die half. Additionally,a locking latch is provided which operates directly across the partingline so as to directly connect the die halves.

Because the die opening and closing cylinder is independent of thelocking mechanism, it is possible to obtain a cushioned closing motionand a quick opening motion.

An additional advantage of the present invention lies in the fact thatthe tie bars which pass between the fixed and movable die halves of thepresent casting machines may be eliminated. The operator is therebygiven complete unhampered access to the dies from all angles. Thisgreatly simplifies the problem of removing and replacing the dies fromtheir platens, and also simplifies the design of casting removingdevices which operate in conjunction with the fixed die half.

Other applications and advantages of the present invention are indicatedin the following detailed description of an embodiment of the invention.The description makes reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of a die casting machine embodying theprinciples of the present invention;

FIGURE 2 is a sectional view through the die moving mechanism of thepresent invention; and

FIGURE 3 is a sectional view of alternative latching arrangement.

The machine is supported'on a base It) which is preferably formed ofwelded plate steel. mounted on the base 10 and is adapted to retain thefixed die half 14. The movable die 16 is supported on a platen 18 whichhas its lower edge resting on hardened and ground ways 20 that arefixedly attached to the upper surface of the base 10.

Four tie rods 22 each have one end fixed to the movable platen 18 andhave their other ends attached to the cylinder end 24 of a hydraulicallyactuated ram generally indicated at 26. Nuts 28 connect the threadedends of the rods 22 to a head plate 30 of the ram 26. As is seen inFIGURE 2 the rods 22 pass through bushings 32 which are disposed in acylinder support bracket 34. The bracket 34 is supported on its outeredges by brackets 36 which are adjustably attached to the base 10 bymeans of bolts 38.

'As is seen in FIGURE 2 the rod 40 of the ram 26 has its outer endfixedly attached to the support plate 34. Therefore, the piston end 42of the rod 40 remains stationary with respect to the base of the machinewhile the cylinder end 24 moves as fluid'is admitted to the various ramchambers. Although fluid may be admitted to the ram chambers in thenormal manner with lines directly connecting to either end of thecylinder 24', it is preferred that fluid connections be made internallythroughv the plate 34 and the rod 40. For this purpose fluid conduits 44are cut in the support plate 34 and attached to the outlet ports of thefluid valve (not shown) at one of their ends. At their other ends theyconnect to two fluid passages 46 in the rod 40. One of the passages 46outlets on one side of the piston 42 while the other fluid passageoutlets on the opposite side.

Cushioning devices which are not shown may be provided to slow down thepiston action as it nears either or both ends of its stroke.

Several advantages in operation result from the fact that the movableplaten 18 is driven by the cylinder end of the ram 26 rather than by therod end as is normally the case. First, the maximum forces of the ramare developed when the dies are opened and the casting has to beejected. This is because the oil pressure injected into the cylinder 24.at the end of the piston not connected to the rod acts against thetotal piston area while oil injected at the rod end acts against thepiston area minus the rod area. Therefore the dies are opened quicklywith a low force and they are closed more slowly with a large for-cc.This is advantageous since no particular force is required to close thedies and this can be done at a higher rate of speed. The closing strokeis also accomplished with a lower force than the opening so that damageto the dies as a result of their slamming together is minimized.

The molten casting material is injected into the cavity formed by thefixed and movable die halves by a shot cylinder 48. The cylinder and theappended shot sleeve are supported directly in the fixed platen 14. Apour hole 50 is provided through which the molten casting material isinserted into the shot cylinder 48.

A fixed platen 12 is j It is to be understood that the die closing andlocking system herein described could also be applied to a hot chambertype machine which is used for casting metals having lower meltingpoints and in which the material is melted directly within the machine.

After the die halves have been closed by the action of the ram 26 aplurality of latches 52 which are arranged about the periphery of thedies close over a lip 53 on the edge of the movable die 16. The latchesare pivotably supported on trunnions S4 and operate in notches 56 cut ina surface of the fixed platen 12. Notches are provided at regularintervals along side of the platens so that as many latches as arerequired maybe utilized. The latches are actuated by small shotcylinders 58 which are supported on the outer side of the fixed platen12. The cylinders 58 also receive their hydraulic fluid through lineswhich are internal of the fixed platen 12.

Because of the short length of these latches 52 and because of thedirect connection they afford between the fixed platen and the movabledie half, they form a specially rigid connection which maintains thedies tightly closed during the pressured injection.

A cavity 60 is provided in the base directly below the die halves sothat the operator has complete access to the dies from all sides.

FIGURE 3 illustrates another embodiment of a die latching mechanism. Thelatching mechanism is supported on a fixed platen 70 of a die castingmachine. The latch is powered by a cylinder '72 which receives anddisposes of hydraulic fluid through lines 74 which are connected topassages 76 within the fixed platen 7%). A latch 78 is supported intrunnion fashion on a pin 80 that is fixed in the sides of the fixedplaten 76 in the same manner that the pins 54 are fixed within theplaten 12. The latch 78 includes a flattened portion 82 which is adaptedto engage a similar surface on the rear edge of the movable die half 84.A recessed curve 86 on the latch connects the section 82 in such amanner as to obviate the possibility of the latch sticking against themovable die surface.

The latch 78 is energized by a wedged drive 85 which is driven by therod 88 of the cylinder 72. The wedge 86 contacts the latch 78 on arounded surface 90 which is also designed to prevent binding. As the rod88 drives the wedge 86 towards the right in FIGURE 3 the latch 78 hasits extended end 82 driven downward. The wedge 86 is also connected tothe latch 78 by means of a link 92 which is pin connected to bothmembers. The connection between the link 92 and latch 78 is achieved bya pin 94 which moves in elongated slot 96 in the link. Therefore, as thewedge 86 is retracted to lift the latch 78 the latch member lagsslightly behind the movement of the wedge. In that manner the wedge hasachieved an initial velocity before the latch 78 is moved. This actioncauses the latch to 'be open with a jerk which frees any possible bindbetween the latch surface 82 and the mating section of the movable diehalf.

This application is a division of application Serial No. 706,851, filedJanuary 2, 1958, for Die Casting Machine.

Having thus described my invention, I claim:

In a die casting machine having a first fixed die half, a second movabledie half, and latching means operable across the parting line of the diehalves to maintain the halves in fixed cooperating relationship, meansfor moving said movable die half into and out of cooperatingrelationship with said first die half, said means comprising: a fluidactuated ram having its piston end fixed with respect to said first diehalf; at least a pair of fluid passages passing through a portion ofsaid first fixed die half and the rod of said cylinder and terminatingon both sides of the piston of said cylinder whereby hydraulic fluid maybe admitted into the cylinder on either side of said piston; and aplurality of tie rods connecting the cylinder end of said ram with saidsecond die half, whereby as fluid is admitted or extracted from thechambers of said ram the second die half is moved with the cylinder ofsaid ram.

References Cited in the file of this patent UNITED STATES PATENTS2,526,918 Wilbershied Oct. 24, 1950 2,582,029 Halward Jan. 8, 19522,717,433 McGervey Sept. 13, 1955

